Reviewed by Brian R. Robinson, MD
An embolus is a solid particle that originates in a vein going to the heart and then is pumped by the heart into an artery where it becomes lodged in the arterial lumen (opening), causing blood flow to be blocked. When this happens, the result is an arterial embolism.
In many cases, an arterial embolism is caused by a blood clot that forms in the heart during abnormal heart pumping (arrhythmia) or after a heart attack. Cholesterol deposits from atherosclerosis in the arteries, as well as clots that form in the lower extremities and break apart to travel through the blood stream, can also dislodge and block arteries.
In a pulmonary embolism, one of the most dangerous types of embolism, the embolus lodges itself in the pulmonary artery on its way to the lungs, potentially resulting in lung tissue damage (infarction) as well as fluid build-up in the lungs. An embolus in an artery leading to the brain can result in a stroke and consequent brain damage. Embolism of the retina can lead to the complete loss of vision in the affected eye.
An arterial embolism may be detected using a variety of means. For pulmonary embolisms, chest x-rays are effective, and tests of lung function may point to embolism as an underlying cause of breathing difficulty or other pulmonary problems. Doppler ultrasound can also help to pinpoint clotting and flow blockages, especially in the lower extremities. An ophthalmoscope can be used to detect a retinal embolism. There are also a number of risk factors for embolism, such as:
• massive trauma
• oral contraceptive use in women
• prolonged inactivity (such as bed rest or very long flights)
• heart attack
• fractures in the bones of the legs.
These risk factors are more or less the same as those for blood clots, because emboli themselves are tiny blood clots, which have frequently originated from a larger source elsewhere in the body. People who have these risk factors should be monitored closely by their health care practitioners.